bin/live-snapshot

   1 #!/bin/sh
   2
   3 # live-snapshot - utility to manage Debian Live systems snapshots
   4 #
   5 #   This program mounts a device (fallback to /tmpfs under $MOUNTP
   6 #   and saves the /live/cow (or a different dir) filesystem in it for reuse
   7 #   in another live-initramfs session. Look at manpage for more info.
   8 #
   9 # Copyright (C) 2006-2008 Marco Amadori <marco.amadori@gmail.com>
  10 # Copyright (C) 2008 Chris Lamb <chris@chris-lamb.co.uk>
  11 #
  12 # This program is free software; you can redistribute it and/or modify
  13 # it under the terms of the GNU General Public License as published by
  14 # the Free Software Foundation; either version 2 of the License, or
  15 # (at your option) any later version.
  16 #
  17 # This program is distributed in the hope that it will be useful,
  18 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  19 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  20 # GNU General Public License for more details.
  21 #
  22 # You should have received a copy of the GNU General Public License
  23 # along with this program; if not, write to the Free Software
  24 # Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
  25 #
  26 # On Debian systems, the complete text of the GNU General Public License
  27 # can be found in /usr/share/common-licenses/GPL-2 file.
  28
  29 set -eu
  30
  31 . /usr/share/initramfs-tools/scripts/live-helpers
  32 . /etc/live.conf
  33
  34 export USERNAME USERFULLNAME HOSTNAME
  35
  36 PROGRAM="$(basename $0)"
  37
  38 # Needs to be available at run and reboot time
  39 SAFE_TMPDIR="/live"
  40
  41 # Permits multiple runs
  42 MOUNTP="$(mktemp -d -p ${SAFE_TMPDIR} live-snapshot-mnt.XXXXXX)"
  43 SNAP_COW="/live/cow"
  44 SNAP_DEV=""
  45 SNAP_OUTPUT=""
  46 DEST="${MOUNTP}/live-sn.cpio.gz"
  47 SNAP_TYPE="cpio"
  48 DESKTOP_LINK="/home/${USERNAME}/Desktop/live-snapshot"
  49 SNAP_RESYNC_STRING=""
  50
  51 Error ()
  52 {
  53         echo "${PROGRAM}: error:" ${@}
  54         exit 1
  55 }
  56
  57 panic ()
  58 {
  59         Error ${@}
  60 }
  61
  62 Header ()
  63 {
  64         echo "${PROGRAM} - utility to perform snapshots of Debian Live systems"
  65         echo
  66         echo "usage: ${PROGRAM} [-c|--cow DIRECTORY] [-d|--device DEVICE] [-o|--output FILE] [-t|--type TYPE]"
  67         echo "       ${PROGRAM} [-r|--resync-string STRING]"
  68         echo "       ${PROGRAM} [-h|--help]"
  69         echo "       ${PROGRAM} [-u|--usage]"
  70         echo "       ${PROGRAM} [-v|--version]"
  71 }
  72
  73 Help ()
  74 {
  75         Header
  76
  77         echo
  78         echo "Options:"
  79         echo "  -c, --cow: copy on write directory (default: ${SNAP_COW})."
  80         echo "  -d, --device: output snapshot device (default: ${SNAP_DEV:-auto})."
  81         echo "  -o, --output: output image file (default: ${DEST})."
  82         echo "  -r, --resync-string: internally used to resync previous made snapshots."
  83         echo "  -t, --type: snapshot filesystem type. Options: \"squashfs\", \"ext2\", \"ext3\", \"jffs2\" or \"cpio\".gz archive (default: ${SNAP_TYPE})"
  84         echo
  85         echo "Look at live-snapshot(1) man page for more information."
  86
  87         exit 0
  88 }
  89
  90 Usage ()
  91 {
  92         Header
  93
  94         echo
  95         echo "Try \"${PROGRAM} --help\" for more information."
  96
  97         exit 0
  98 }
  99
 100 Version ()
 101 {
 102         echo "${PROGRAM}"
 103         echo
 104         echo "Copyright (C) 2006 Marco Amadori <marco.amadori@gmail.com>"
 105         echo "Copyright (C) 2008 Chris Lamb <chris@chris-lamb.co.uk>"
 106         echo
 107         echo "This program is free software; you can redistribute it and/or modify"
 108         echo "it under the terms of the GNU General Public License as published by"
 109         echo "the Free Software Foundation; either version 2 of the License, or"
 110         echo "(at your option) any later version."
 111         echo
 112         echo "This program is distributed in the hope that it will be useful,"
 113         echo "but WITHOUT ANY WARRANTY; without even the implied warranty of"
 114         echo "MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the"
 115         echo "GNU General Public License for more details."
 116         echo
 117         echo "You should have received a copy of the GNU General Public License"
 118         echo "along with this program; if not, write to the Free Software"
 119         echo "Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA"
 120         echo
 121         echo "On Debian systems, the complete text of the GNU General Public License"
 122         echo "can be found in /usr/share/common-licenses/GPL-2 file."
 123         echo
 124         echo "Homepage: <http://debian-live.alioth.debian.org/>"
 125
 126         exit 0
 127 }
 128
 129 Parse_args ()
 130 {
 131         # Parse command line
 132         ARGS="${*}"
 133         ARGUMENTS="$(getopt --longoptions cow:,device:,output,resync-string:,type:,help,usage,version --name=${PROGRAM} --options c:d:o:t:r:,h,u,v --shell sh -- ${ARGS})"
 134
 135         eval set -- "${ARGUMENTS}"
 136
 137         while true
 138         do
 139                 case "${1}" in
 140                         -c|--cow)
 141                                 SNAP_COW="${2}"
 142                                 shift 2
 143                                 ;;
 144
 145                         -d|--device)
 146                                 SNAP_DEV="${2}"
 147                                 shift 2
 148                                 ;;
 149
 150                         -o|--output)
 151                                 SNAP_OUTPUT="${2}"
 152                                 shift 2
 153                                 ;;
 154
 155                         -t|--type)
 156                                 SNAP_TYPE="${2}"
 157                                 shift 2
 158                                 ;;
 159
 160                         -r|--resync-string)
 161                                 SNAP_RESYNC_STRING="${2}"
 162                                 break
 163                                 ;;
 164
 165                         -h|--help)
 166                                 Help
 167                                 ;;
 168
 169                         -u|--usage)
 170                                 Usage
 171                                 ;;
 172
 173                         -v|--version)
 174                                 Version
 175                                 ;;
 176
 177                         --)
 178                                 shift
 179                                 break
 180                                 ;;
 181
 182                         *)
 183                                 Error "internal error."
 184                                 ;;
 185
 186                 esac
 187         done
 188 }
 189
 190 Defaults ()
 191 {
 192         # Parse resync string
 193         if [ -n "${SNAP_RESYNC_STRING}" ]
 194         then
 195                 SNAP_COW=$(echo "${SNAP_RESYNC_STRING}" | cut -f1 -d ':')
 196                 SNAP_DEV=$(echo "${SNAP_RESYNC_STRING}" | cut -f2 -d ':')
 197                 DEST="${MOUNTP}/$(echo ${SNAP_RESYNC_STRING} | cut -f3 -d ':')"
 198
 199                 case "${DEST}" in
 200                         *.cpio.gz)
 201                                 SNAP_TYPE="cpio"
 202                                 ;;
 203
 204                         *.squashfs)
 205                                 SNAP_TYPE="squashfs"
 206                                 ;;
 207
 208                         *.jffs2)
 209                                 SNAP_TYPE="jffs2"
 210                                 ;;
 211
 212                         ""|*.ext2|*.ext3)
 213                                 SNAP_TYPE="ext2"
 214                                 ;;
 215                         *)
 216                                 Error "unrecognized resync string"
 217                                 ;;
 218                 esac
 219         elif [ -z "${SNAP_OUTPUT}" ]
 220         then
 221                 # Set target file based on image
 222                 case "${SNAP_TYPE}" in
 223                         cpio)
 224                                 DEST="${MOUNTP}/live-sn.cpio.gz"
 225                                 ;;
 226
 227                         squashfs|jffs2|ext2)
 228                                 DEST="${MOUNTP}/live-sn.${SNAP_TYPE}"
 229                                 ;;
 230
 231                         ext3)
 232                                 DEST="${MOUNTP}/live-sn.ext2"
 233                                 ;;
 234                 esac
 235         else
 236                 DEST="${SNAP_OUTPUT}"
 237         fi
 238 }
 239
 240 Validate_input ()
 241 {
 242         case "${SNAP_TYPE}" in
 243                 cpio|squashfs|jffs2|ext2|ext3)
 244                         ;;
 245
 246                 *)
 247                         Error "invalid filesystem type \"${SNAP_TYPE}\""
 248                         ;;
 249         esac
 250
 251         if [ ! -d "${SNAP_COW}" ]
 252         then
 253                 Error "${SNAP_COW} is not a directory"
 254         fi
 255
 256         if [ "$(id -u)" -ne 0 ]
 257         then
 258                 Error "you are not root"
 259         fi
 260 }
 261
 262 Mount_device ()
 263 {
 264         case "${SNAP_DEV}" in
 265                 "")
 266                         # create a temp
 267                         mount -t tmpfs -o rw tmpfs "${MOUNTP}"
 268                         ;;
 269
 270                 *)
 271                         if [ -b "${SNAP_DEV}" ]
 272                         then
 273                                 try_mount "${SNAP_DEV}" "${MOUNTP}" rw
 274                         fi
 275                         ;;
 276         esac
 277 }
 278
 279 Do_snapshot ()
 280 {
 281         case "${SNAP_TYPE}" in
 282                 squashfs)
 283                         EXCLUDE_LIST="$(mktemp -p ${SAFE_TMPDIR} live-snapshot-exclude-list.XXXXXX)"
 284                         echo "./${EXCLUDE_LIST}" > "${EXCLUDE_LIST}"
 285                         cd "${SNAP_COW}"
 286                         find . -name '*.wh.*' >> "${EXCLUDE_LIST}"
 287                         cd "${OLDPWD}"
 288                         mksquashfs "${SNAP_COW}" "${DEST}" -ef "${EXCLUDE_LIST}"
 289                         rm -f "${EXCLUDE_LIST}"
 290                         ;;
 291
 292                 cpio)
 293                         ( cd "${SNAP_COW}" && find . -path '*.wh.*' -prune -o -print0 | cpio --quiet -o0 -H newc | gzip -9c > "${DEST}" ) || exit 1
 294                         ;;
 295
 296                 ext2|ext3)
 297                         DU_DIM="$(du -ks ${SNAP_COW} | cut -f1)"
 298                         REAL_DIM="$(expr ${DU_DIM} + ${DU_DIM} / 20)" # Just 5% more to be sure, need something more sophistcated here...
 299                         genext2fs --size-in-blocks=${REAL_DIM} --reserved-percentage=0 --root="${SNAP_COW}" "${DEST}"
 300                         ;;
 301
 302                 jffs2)
 303                         mkfs.jffs2 --root="${SNAP_COW}" --output="${DEST}"
 304                         ;;
 305         esac
 306 }
 307
 308 Clean ()
 309 {
 310         if [ -z "${SNAP_RESYNC_STRING}" ] && echo "${DEST}" | grep -q "${MOUNTP}"
 311         then
 312                 echo "${DEST} is present on ${MOUNTP}, therefore no automatic unmounting the latter." > /dev/null 1>&2
 313         else
 314                 umount "${MOUNTP}"
 315                 rmdir "${MOUNTP}"
 316         fi
 317 }
 318
 319 Main ()
 320 {
 321         Parse_args "${@}"
 322         Defaults
 323         Validate_input
 324         trap 'Clean' EXIT
 325         Mount_device
 326         Do_snapshot
 327 }
 328
 329 Main "${@:-}"